Artificial leg



Sept. 18, 1951 I J. G. CATRANIS 2,568,051

ARTIFICIAL LEG (THIGH MUSCLEKNEE LOCK CONTROL) Filed Oct. 10, 1947 6 Sheets-Sheet 1 IN V EN TOR.

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Sept. 18, 1951 J. G. CATRANIS ARTIFICIAL LEG (THIGH MUSCLE KNEE LOCK CONTROL) 6 Sheets-Sheet 5 Filed Oct. 10, 1947 INVENTOR.

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ARTIFICIAL LEG (THIGH MUSCLE KNEE LOCK CONTROL) Sept. 18, 1951 6 Sheets-Sheet 4 Filed 001;. 10, 1947 .w in v, m M mfi My i a J. G. CATRANIS Sept. 18, 1951 ARTIFICIAL LEG (THIGH MUSCLE KNEE LOCK CONTROL) Filed Oct. 10, 1947 6 Sheets-Sheet 5 INVENTOR Jaim 6 fiairaflw Sept. 18, 1951 J. G. CATRANIS 2,568,051

ARTIFICIAL LEG (THIGH MUSCLE KNEE LOCK CONTROL) Filed Oct. 10, 1947 6 Sheets-Sheet 6 INVEN T 0R.

Patented Sept. 18, 1951 ARTIFICIAL LEG (THIGH MUSCLE KNEE LOCK CONTROL) John G. Catranis, Syracuse, N. Y. Application October 10, 1947, Serial No. 779,011

15 Claims.

This invention relates to artificial legs for above-the-knee amputees, and more particularly to means for controlling the movement of the lower leg about the knee joint, during the walking cycle and other operations, as standing up and sitting down, ascending and descending steps, inclines, or ramps, etc.

It has for its object a control sensitive to and operated involuntarily by the tensioning and relaxation of the thigh muscles, as the quadricep tendon, to control the operation of the knee lock, or brake, during normal walking, ascending and descending stairs and inclines, sitting down, etc., in accordance with, or in proportion to, the tensioning and relaxation of the thigh muscles, and also such control operated voluntarily to consciously tension the thigh muscles for ascending and descending at different rates. In other words, the invention has for its object a control for the knee lock or brake operated by the voluntary or unconscious action of the thigh muscles or quadriceps tendon itself during the walking operation, in contradistinction to the bodily movement of the entire stump of the amputee in the socket of the artificial leg to mechanically effect, as through links or levers, the operation of a knee lock. In other words, the action of the thigh muscles takes place the same as in a normal leg and the action, that is, the tensioning and relaxation movement is transferred tosome mechanical device replacing muscles of the amputated lower leg.

It also has for its object a knee lock or brake operated by the control sensitive to motion transmitted through the movement of the thigh muscles involuntarily, or voluntarily.

The invention consists in the novel features and in the combinations and constructions hereinafter set forth and claimed.

In describing this invention, reference is had to the accompanying drawings in which like characters designate corresponding parts in all Y the VieWS.

Figures 1 and 2 are, respectively, a side elevation and a front elevation, partly in section and partly broken away, of a leg embodying this invention.

Figure 3 is a sectional view on line 3-3, Figure 2.

Figure 4 is an enlarged fragmentary sectional view of the upper front side of the stump socket of the leg and one form of quadriceps control carried thereby, the knee lock or brake, and the motion transmitting means between the control and the brake, being shown fragmentarily in elevation.

Figure 5 is a plan view of the knee lock or brake.

Figure 6 is a sectionon line 66, Figure 5..

Figures '7, 8 and 9 areviews similar to Figures 4, 5 and 6, of a slightly modified form of the thigh muscle control and the knee lock or brake.

Figures 10, 11, 12, 13, 14, 15, 16 and 17 are elevations partly in section of the leg showing the relative position of parts of the control and the knee lock or brake duringa walking cycle.

Figures 18 and 19 are'views similar to Figures 10 to 17 showing the relative positions of the parts of the control and the knee lock or brake during a sitting down operation.

The artificial leg consists of a socket l for fitting the stump S of the amputee, a lower leg structure 2 pivoted to the-lower end .of the socket to swing forward and backward during walking, climbing and descending, etc., a foot 3 pivoted at its ankle to the lower leg structure, a control 4 including a muscle operated mechanism carried by the socket in position to be actuated in varying amounts by the tensioning and relaxation of the thigh muscles during the use of the leg, a knee brake or look 5 controlling the swinging movement of the lower leg and its angular positions relative to the socketv during changes in the. angular position of the socket and stump about the axis of the hip joint, and including an actuator 6, and motion transmitting means 1 between the prime mover and the actuator.

The socket l is of any suitable construction and material, and of such size as to fit the stump of the amputee, the top edge being of the outline shown to conformv to the body, hips, ischial seat or buttock of the subject. The socket is provided at its lower end with a bracket or kneejoint housing 8 rigid therewith and provided with a tubular hearing or sleeve 9 in which is mounted a transverse knee joint shaft II), this being tubular for the sake of lightness. The bracket or housing 8 is provided with two pairs of downwardly extending radial webs or arms ll, l2, of difierent radial lengths and angles relative to the axis of the shaft I0, these serving as rock arms of different radii relative to the axis of the knee joint or shaft [0, and of different radial lengths. The fibula link and knee lock are pivoted to these arms. The socket is usually provided with a. ventilator I3.

The control 4 for the knee lock or brake is here shown as arranged to be operated by the action of the muscles on the front side of the stump, as the quadricep eXtensor tendon which has varying movements during tensioning, as when the leg is lifted, or when the weight of the body is applied to the leg, and during relaxation, as during the discontinuance or easing of strains thereon. Two forms of control are shown. The preferred form is that shown in Figure 4 and in most of the other figures. A slightly modified form is shown in Figure 7.

The control 4 includes a body l4, a muscle operated member, as a lever pivoted to the body and arranged to be actuated by the thigh muscles, and motion transmitting connections between the lever and the operatin member or actuator 6 of the knee lock and brake. Preferably, the control includes levers arranged to' be operated successively, the last lever to be operated functioning in operations other than normal walking, as when sitting down etc., as when the stump is lifted to a high angle about the hip joint. More'specifically, the control 4 includes the body l4, successively operated muscle operated levers l5, [6, arranged in position to be successively operated from normal by the reasoning of the thigh muscles, a head I! to which the motion of the' levers individually and collectively: transmitted, and motion transmitting connections, as 1. The support 14 is a housing" orbr'acket-fiXed to'the outer side of the upper front side wall of the socket I,

I as by screwsonbolt's 1' 8; The lever I is an angle lever pivotedat [9 at its'angle-to the support l4 at the top edge of the socket and having a forwardly extending arm 26 and an upwardly extending arm 2| located to" be pressed against by he quadriceps and acme-ted thereby. The lever I5 is in two sections adjustable to vary the angular relation of onesecti'o'ri, as" theu'p'war'd extending arm 2|, relative toth' other section or for- 11 ward extending armill, as will be presently described. The'l'eve'f Wis pivoted cit-'22 to" the upper end of the arm 2| and extends upward; and forward therefrom, and thefniotiofithereof is transmitted' re the head r1 through a link is pivoted at its" upper and' i'ewer' enqat g4 and 25 to the lever l5 and to the head 11'. The lever arm 20 rigid with the head h surfaces of the lever arm 2| and the lever fB' ar'ecurvilinear or arcuate' to conform to'th'e'leg" andbody, and may be covered by e pea. V I I As previously stated, are lever 15 is in two sections, t e arms 20, 21', constituting the sections.

The sectiens are adjustable ccver'y the angle between them to bestadapt the" arm 2i to the quadricep tendon of theaiiiput. As shown, the adiustmeiit is effected by a; st screw 26 threading through an angular lug on the lever arm against the confronting side of the lever arm 2|. Both sections or arms 20, 2|, of the angle lever l5 are mounted on the'pivo't IQ of the lever.

The motion transmitting connections (designated generally by the numeral T) between the head I! and the a'kialualto'r .6 er the knee lock or brake, in the form shown in igure" 4, includes a reciprocatingpush plunger 21 having a stem slidable in a bushing 23 threading in a bore in block 23 of the support l4, and a push and pull, or Bowden wire 30, within atubular sheath 3 I. The wire is connected at its lower end to a clevis pivoted to the actuator The sheath 3 I is interposed between the block 29 and the clevis 32.

The head I1 is provided with an antiffiction roller 33 which thrusts against the head of the plunger 21; h returningsprin 34 is interposed between the head of the plunger and the opposingend of the bushing 28. The bushing 28 is adjustable axially through a suitable work hole to adjust the loading of the spring- 34 to the quadricep action of the amputee.

ill

In Figure 7, the thigh muscle control is hydraulic. The muscle operated mechanism is a compressible bulb 35 carried by a bracket or support 36 at the upper edge of the socket l in position to be compressed and released under the tensioning and relaxation of the quadriceps. The motion is transmitted from the bulb 35 to the actuator for the knee lock or brake through a hydraulic pipe line 31 communicating with the cylinder of a motor, the piston of which operates an actuator corresponding to the actuator 6, as will hereinafter be more fully described. The bulb 35, support 36 and adjacent portion of the tube 31 are enclosed by a fabric or leather cover 38.

The lower leg and foot structure is made up of a frame or tibia members, the knee lock or brake structure, and the fibula.

The knee lock or brake here illustrated is hydraulic and includes a hydraulic cylinder and piston therein having relative movement and constituting a link pivoted at one end to the bracket 8eccentric to the axis of the shaft [0, and at its other end to a pivot on which the foot 3' is pivoted at its ankle, and valving for the hydraulic fluid in a full, closed circuit including by-passes from one end of the cylinder to the other around the piston, the valving being operated by the actuator 6 which is controlled in its operation by the control 4 operated by th thigh muscles.

As here shown,- the piston 40 and its rod 4| are one section of the link, the rod 4| being pivoted at 42 to the arm I2 of bearing bracket 8; and the cylinder 43 is the other section of the link, this having a tail rod 44' mounted at its lower end on a pivot 45, Figures 1 and 2, carried by a bracket 46 at the lower ends of frame braces or tibia members 41 which are pivoted at their upper ends on the ends of the tubular shaft Ill. The foot 3 is formed with a recess 48 receiving the bracket 45, and the side walls of the recess are pivotally mounted on the ends of the pivot 45. The pivot is the ankle joint of the foot and is carried by the tibia members 41. The piston 40 has a tall rod 49 slidable in' the tail rod 44 of the cylinder to equalize the displacement of the fluid from one side of the piston to the other, or to equalize areas on opposite sides ofthe piston.

The valving includes a valve body carried by the cylinder and formed with a by-pass around the piston 40 from one end of the cylinder to the other, a normally open throttle valve operable from fully open position to fully closed position through different partly open positions, by the actuator 5 which, in turn, is controlled by the thigh muscle control 4. The throttle valve for extreme sensitiveness of control includes two normally open separate valve members, one closing fully ahead of the other and located in its own by-pass around the last valve to close. The valving also includes a relief valve and a sudden shock absorber or accumulator.

The body 50 of the valving is formed with a bypass 5| around the piston 40 in which is located one member of the throttle valve, this being shown as a needle valve 52. The body is also formed with a second by-pass 53 connecting portions of the by-pass 5! around the needle valve 52, the by-pass 53 having a normally open valve 53 therein arranged to fully close in advance of the needle valve. The valve 54 is shown as a spring pressed ball which also serves as a check valve when closed, and opens when the pressure of the fluid becomes greater in the cylinder below the piston 40 than above the piston. The upper end of the cylinder 43 is usually the high presand from closed position by a rocking movement e'fiected by the operating member or actuator 6.

The needlevalve is shown as provided with an enlarged shank 55 having coarse threads 56 turning in a bore in the body 50. The actuator 6 is a lever or rock arm on the outer end of the shank outside of the body 59. The valve or ball 54 is' actuated or controlled in its closing movement by its spring 51 by the operating member or actuator 6, as through a push pin 59 working axially in the by-pass 53, and thrusting against the ball ,54 to hold it off its seat against its spring 51 and operated from the actuator 6 through motion transmitting connections.

As shown in Figures and 6, the by-pass 53 includes a widened portion or recess 6|] in which the valve 54 is located, the recess intersecting the vby,,-pass 5| between the valve 52 and the upper end of the cylinder 43. The by-pass 53 opens at its lower end into the by-pass 5| between the throttle valve 52 and the lower end of the cylinder 43. The pin 58 is guided in its movement by a head 62 slidable in a thimble or bushing 63 threading into the body 50.

The motion transmitting connection comprises a carrier as an arm 64 connected to the head 62 as by a screw 65, the arm extending laterally parallel to the axis of the needle valve 52, and a link 66 pivoted at one end at 61 to the actuator lever ,6, and at its other end at 68 to the outer end of the arm 54. A returning spring 69 acts on the arm 64 inline with the pin 58 to hold the valve 54 open, or offits seat 59, against the closing action of the spring 51.

, The setting of the throttle valves 52, 54, is such that upon initial actuation of the control 4 by the initial tensioning of the thigh muscles, the actuator arm 6 is moved downward through the lever arm 28 of the control 4, plunger 21, Bowden wire36and clevis 32, a certain amount, say 4",

; Figure 4, this being sufiicient to permit the valve 54 to fully close and the needle valve 52 to but partly close, and that upon further actuation of the control 4 by further tensioning of the thigh muscles, the actuator arm 6 is shifted to say a ang1e and fully closes the needle valve 52 so that now the by-pass 5| is fully closed and the piston locked from movement and hence, the knee joint looked as the folded toggle formed by the arm l2 and the rod of the locked or stalled piston 40 is locked from further folding and unfolding movement. In the valving for the modified form of control 'shown in Figure 7, the force for operating the .throttle valve members 52 and 54 is applied to the push pin 58 and transferred through the carrier arm 64 and link 66- to the actuator 6A for the valve 52. As seen in Figures '7, 8 and 9, the pipe 31 for transferring the hydraulic pressure set up in the bulb control 35 by the tensioning of the thigh muscles, is transferred to a cylinder chamber "in the bushing 63 and acts on a pistonH" to throttle valve mounting and push pin mounting, comprises an accumulator for compensating for expansion and contraction of the hydraulic fluid undervarying temperatures is built into the system, and also permitting additionalmovement of the piston under certain conditions when both throttle valve'members are closed. The accumulator, as here illustrated, includesa floating plunger 15 at one end of the cylindnas the upper end, pressed downward against the body of fluid filling the cylinder 43, toward'the piston 48,-anda spring 16 between the plunger 15 and a spring abutment 11 slidable in the head 18 of the cylinder. The abutment yields downward under the weight of the body applied to the socket when the leg isextended or straight, and acts as a buffer, that is, when both throttle valve members 52, 54, are fully closed, and the leg is straight with the weight of the body applied thereto. This buiTer action is effected by a stop shoulder 18A on the piston rod 4| above the cylinder 43 and located to engage a portion of the abutment 11 which extends through the cylinder head 18. The shoulder 18A, plunger 15, abutment 11, and spring 16 assembly serve as a yielding sto to limit the knee joint movement of the lower leg into straight position with the socket, and hold it from-buckling rearward. In addition, the plunger 15 and spring 16 act as an accumulator to store energyupon pressure applied to'the fluid'above the piston "40 by upward pull on the piston rod when the knee tends to buckle forward and the by-passes are closed.

The accumulator also includes a follow-up floating piston 19 at the lower end of the cylinder which prevents the formation of a'space'or vacuum below the piston 46 when the plunger 15 moves upward and compresses the spring 16 when the by-passes are closed. There is a vented space 43A at the lower end of the cylinder 43 below the follow up piston 19 suificient to'permit the piston 48, body of fluid below it, and the follow up piston 19 to shift when the spring 16 is compressed by the shoulder 18A.

The system also embodies a relief or overload valve which is locatedin a by-pass 8| around both throttle valves 52, 54. The spring 82 of the relief valve is of greater weight, or stronger, than the accumulator spring 16 and opens to release the accumulator spring and let the excess fluid pass through the by-pass 8| to the lower end of the cylinder.

The movement of the foot 3 about the ankle joint or pivot 45 is controlled by a link 82 performing a function somewhat analogous to the fibula of a natural leg. It is in two sections having relative axial movement. One section is pivoted at 83 to the shorter arm H of the knee joint bearing bracket 8, this pivot 83 being located in the rear of the arm I 2 and of a shorter radius than the arm l2 to which theupp'er end of the piston rod 4| is pivoted. The other lower end of the fibula link is pivoted at 84 to the instep area of the foot in advance of the ankle pivot 45 so that the fibula and the link consisting of the cylinder 43 and piston 40 cross each other. The

' sections 'of the link 82 are joined together by a slip friction joint at 85 where 1' they telescope. The link 82 is acted on by a spring 86 which tensions during flexing of the knee joint andacts to swing the lower leg forward from flexed to extended position straight with the socket. 'The sections of the fibula link separate at the slip joint after theleg is swungforward and while extended or straight, the heel is placed on the floor, and the toe=up,the weight of the body applied to the heel through theextended leg, and

the foot: moves about the angle joint to flatposition on the floor (Figures 11 and 12). When the weight isapplied to the heel of the straightened leg,v as in Figure 11, the foot fulcrums about the leg. moves forward with the foot flat on the floor in the position shown in Figures 13 and 14 when, with the weight of the body still on the artificial leg, the amputee rises on the toe of the foot. The movement of the foot about the ankle joint 45 in to a position flat on the floor, Figure 12, compresses, or energizes, the pad 81, facilitating the starting. of the leg, or the tibia, toward the position shown in Figure 13, as the body progresses forward. The facilitating of the starting of the leg is as follows. The reaction of the compressed pad 81 is upward to the tibia 41, the bracket 46, ankle. joint 45, and the tail rod 44, of the cylinder 48, as the artificial leg shifts its angle due to the hip joint progressing forward in the position shown in Figure 13. During this shift, the tibia 41 changes its angle from a position, Figure 12, inthe rear of a vertical line intersecting the pad 81' toward a position in which the tibia inclines forward in front of such a line, Figure 13, so that the reaction of the pad tends to bend the knee at the knee joint l0. As the cylinder 43, and hence the piston rod 4| likewise changes its angle to a greater degree, as the pivot 42 is eccentric to the knee pin 10, and further as. the reaction impulse of the pad 81 is transmitted to the tail rod 44 of the cylinder through the bracket 48,-the

lower leg is given, by the reaction of the pad 81,

a momentary boost in its swinging movement from the position shown Figure 12 to that shown in Figure 13.

The radial angle of. the pivot 83-, relative to the knee joint H), is such that the slip joint 85 of the 1 fibula link 8.2 is takenup in all positions of the leg and foot, except when the knee is bent and the foot planted on the floor after the extended le with the heel pressing on the floor, is shifted from the position shown in Figure 11 to that shownin 1 Figure 12 wherein. the foot has shifted about the ankle pivot 45 into position wherein the foot is flat on the fioor. During this pivoting of the foot,

the pivot 83 moves in an upward forward arc about the axis of the knee joint In, and the lower section of the link moves downward as the foot pivots about the ankle joint and opens the gap in the friction slip joint 85, which gap is taken up when the leg moves into the position shown in Figure 13 and thereafter acts as a brace on the foot during downward force of the fibula link when the weight is on the right foot, and friction clutch fashion when the weight is removed from the foot toreset the foot at its normal angle at the ankle joint while the leg is passing through the positions shown in Figures 16, 1'7, I and 1.1, in the normal walking cycle. In the normal walking cycle, the foot is swung forward while held off the ground when passing from the Figure 17 position to the Figure 11 position, through the Figure position.

- with the angle of the socket and lower leg, as seen in Figures 14, I5, 16 and 17. The thigh muscles are not under tension, or but partly so, as the weight of the body is wholly, or partly, removed from the artificial leg when in the positions shown in Figures 14 to 17 inclusive. Hence,. at least the throttle valve 52 is open and. thefluid can by-pass from the upper to the lower end of the cylinder 43, and the fluid merely retards dash-pot fashion the forward swinging momentum of the leg under the pull of the spring. 86. However, the arm [2, or the pivot 42, also changes its angular position slightly relative to the axis of the knee joint I!) and raises the piston 40, or changes its relative height in the cylinder 43 when the knee joint is flexing and the weight of the body is on the artificial leg, all as seen in Figures 12 and 13. This slight change in the relative position of the piston 40 in the cylinder 43 shifts the accumulator piston 15 upward against the returning action of the spring 16.

In operation, assume that the amputee has an artificial right leg and is standing straight with both feet together, and is about to step forward with his right foot. The leg is extended or straight, as seen in Figure 10. The actuator Biof the knee lock is in normal position, or at a 0 angle, and both valves 52, 54, open. He first shifts his weight to the left foot. He then swings the artificial leg forward about the hip joint and While extended, places the heel on the floor (Figure 11). The thigh muscles tension and operate the control 4 which operates the operating memher or actuator 6 fully to the 15 angle to close both the valves 52, 54, and lock the knee joint so that the leg is locked from buckling at the knee. The leg can not bend backward at the knee as the stop shoulder 18A will engage the abutment I1. The lever 15 of the control effects the actuation of the plunger 21, or motion transmitting connections to the operating member or actuator 5. The lever l6 and link 23 merely idle. As the body progresses forward, the leg bends slightly at the knee joint due to the fact that the foot tends to lag behind while on the fioor before or while the hip of the artificial leg is being lifted slightly preliminary to taking a step forward, in order that the toe of the foot may not drag, and the piston is pulled up slightly compressing the spring 16 while the valves 52, 54, are fully closed. The movement of the foot about the ankle pivot 45, while the rear edge of the heel is on the floor. causes the foot to come fiat on the floor separating the sections of the fibula link at the friction slip joint 85, Figure 12. Because the thigh muscles remain under tension, the operating member or actuator 6 remains in the 15 angle. During the forward progress of the body, the lower leg or tibia swings about the ankle joint 45 toward a vertical line facilitating the downward movement of the foot about the heel as a fulcrum by pressing down on the ankle pivot 45 and separating the sections of the fibula link at the slip joint 85. During the bending of the knee, the radial positions of the arms I I, I2, rigid with the socket, or the pivots 42, 83, change relative to the piston rod 4| and the fibula link pivoted thereto. Due to the change of the upward angle of the arm l2, the piston 43 is raised in the cylinder 40, and also incidentally widens the gap at the slip joint of the fibula link. During the raising of the piston 43, the plunger 15 is pressed upward compressing its spring 16, Figures 12 and 13.

As the body progresses forward, the tibia members 41 on the lower leg change their angle in an inclined position forward about the ankle pivot 45, as shown in Figure 13 wherein the knee joint shaft [0 is in a vertical plane in front of the ankle pivot 45, and the gap in the slip joint of the fibula is taken upor closed. The-control 4 remains under the tension of the thigh muscles,

the actuator under the 15 knee locking angle, and the accumulator spring 16 under compression.

Theamputee, while carrying his weight on the artificial or right leg through the positions shownin Figures 11, 12 and 13, has been swinging his left leg forward about the hip to take a stepwith the left leg, and plants, his left foot on the floor in advance of the right foot, and shifts his weight from the right to the left foot. Now the rightleg is in the position shown in Figure 14. The shifting of the weight to the left foot causes the thigh muscles of the stump of the right leg to partly relax, first partly releasing the knee lock, or moving the actuator to the 4 angle when the throttle valve 52 is partly open, permitting the leg to flex rearward about the knee joint [0. The amputee then lifts the right leg from the hip joint to lift the foot off the floor. In Figure 16, the thigh muscles are relaxed because the weight of the body is on the left leg and the control 4 is normal, the actuator in 0 position, and the knee fully unlocked. When fully unlocked and the right leg holding the foot raised off the floor, the lower leg, or the tibia members swing forwardly under the action of the spring 86 dampened by the dash-pot action of the piston 40, through the positions shown in Figures 16 and 1'7. At this point, the left leg is carrying the weight and the toe of the left foot is on the floor in the rear of the artificial leg. The right leg is about to take a new step and begins to extend by lifting the stump and partly tensioning the thigh muscles and operating the control 4 and the actuator to the 4 angle in which the knee lock is only partly locked by the closing of the valve 54 only. This dampens the swinging momentum of the right leg about the knee. joint against overthrow under the pull of the springafi which is additionally loaded while the lower leg is passing through the positions shown in Figures 12, 13, 14 and 15, and which reacts when the lower leg is moving through the position shown in Figures 16 and 17, and before the heel is again planted on the floor, Figure 11. The leg then assumes the fully extended and locked position Figure 11, with the heel on the floor and the weight applied to the leg. In repeated walking cycles, the leg does not stop in the positionshown in Figure 10 with the foot on the floor, but swings from the position shown in Figure 17 to that shown in Figure 11.

In ascending and descending steps, ramps, etc., and in sitting down where the upper leg takes a horizontal position at periods, or takes a greater angle to the body about the hip joint than in normal walking, the control lever l6 comes into action successively to the lever l5 and acts after the thigh muscles have relaxed, as seen in Figures 18 and 19. In Figures 18 and 19, the quadriceps are allowed to relax when the amputee is nearly seated, but lever 16 of the control operates the knee lock actuator 6 to permit the valve 54 to close. This brakes the sitting down operation and lets the amputee shift some of the strain of sitting down from the natural leg to the artificial leg. In standing up-from sitting position at first, the amputee must raise himself with his natural leg, or lift himself until the levers 16 are not motivated. At any time the amputee tensions the thigh muscles, the knee lock locks and holds the leg. from buckling at the knee.

.What I claim is:

1. Acontrol for artificial legs which includes a 10 stump socket, a lower leg hinged to the socket by a knee joint, a knee lock and brake, which knee lock and brake includes an actuator member; the control including a muscle actuated mechanism carried by the socket in position to receive motion from the quadriceps extensor tendon during the tensioning and relaxation of the thigh muscles, and motion transmitting means between the muscle actuated mechanism and the knee lock and brake actuator.

2. A control for artificial legs which includes a stump socket, a lower leg hinged to the socket by a knee joint, a knee lock and brake, which knee lock and brake includes an actuator member; the control including a muscle actuated mechanism carried by the socket including two members arranged to successively coact with the quadriceps extensor tendon to receive motion therefrom during tensioning and relaxation of the quadriceps extensor tendon, and a head common to both members, and motion transmitting means between the head and the knee lock and brake actuator member. v 3. A control for artificial legs which includes'fa stump socket, a lower leg hinged to the socket by a knee joint, a knee lock and brake, which knee lock and brake includes an actuator member; the control including a muscle actuated mechanism carried by the socket including a'support attachable to the upper edge of the socket, an angle lever pivoted at its angle to the support and having one arm located to coact with the thigh muscles to be motivated thereby during tensioning and relaxation of the muscles, and motion transmitting connections between the other arm of the lever and the actuator member. 4. A control for artificial legs which includes a, stump socket, a lower leg hinged'to the socket by a knee joint, a knee lock and brake, which knee lock and brake includes an actuator mem ber; the control including a muscle actuated mechanism carried by the socket including a sup port attachable to the upper edge of the socket, two levers and a head, one lever being an angle lever pivoted at its angle and having an upward extending arm above the edge of the socket in position to coact with the quadriceps extensor tendon of the stump and an outward, extending arm carrying the head, the second lever being pivoted to the upper end of the upward arm of the first lever and overhanging the head and the outward extending arm of the first lever, a link pivoted at its ends to the second lever and to the head, the second lever being located to be actuated successively relative to the first lever by the tensioning and relaxation of the quadriceps extenser tendon, and motion trans-,- mitting connections between the head and the knee lock and brake actuator member. 5. A- control for artificial legs which includes a stump socket, a lower leg hinged to the socket by.;a knee joint, a knee lock and brake, which knee lock and brake includes an actuator member; the control including a muscle actuated mechanism carried by the socket in position to receive motion from the quadriceps extensor tensdon during the tensioning and relaxation thereof, and motion transmitting means between the muscle actuated mechanism and'the knee lock and brake actuator member, the motion transmitting means including a Bowden-wire :between the muscle actuated mechanism and, the knee lock and brake actuator member. '1 r 16. A control for artificial legs which. includes a stump socket, a lower leghinged to the socket by a knee joint, a knee lock and brake, which knee lock and brake includes an actuator memher; the control including a muscle actuated mechanism carried by the socket in position to receive motion from the quadriceps extensor tendon during the tensioning and relaxation thereof, and motion transmitting means between the muscle actuated mechanism and the knee lock and brake actuator member, the muscle actuated mechanism including a resilient compressible chamber for a hydraulic fluid carried at the upper edge of the socket in position to be engaged and be compressed and released by the tensionin'g and relaxation of the quadriceps extensor tendon, a hydraulic motor including a piston connected to the knee brake and lock actuator member, and a hydraulic pipe line between the muscle actuated mechanism and. the motor.

7. An artificial leg for above-the-knee amputees including a stump socket, a lower leg including a tibia member hinged by a knee joint to the socket and carrying a foot, a hydraulic knee lock and brake carried by the lower leg and including a link which includes a cylinder pivoted to the tibia member at the foot end thereof, and l a piston having its rod pivoted to the socket below and eccentric to the hinged axis of the knee joint, a valve body carried by the cylinder and formed with "a by-pass around the piston from one end of the cylinder to the other, a throttle valve membar in the by-pass, an operating member therefor for closing and opening the same, a control on the socket operated by the quadriceps extensor tendon during the tensioning and relaxation thereof, the throttle valve being open during the relaxation of said tendon, and motion transmitting connections between the control and the actuator member for the throttle valve member.

8. An artificial leg for above-the-knee amputees including a stump socket, a lower leg including a tibia member hinged by a knee joint to the socket and carrying a foot, a hydraulic knee lock and brake carried by the lower leg and including a link which includes a cylinder pivoted to the tibia member at the foot end thereof, and a piston having its rod pivoted to the socket below and eccentric to the hinged axis of the knee joint, a valve body carried by the cylinder and formed with a by-pass around the piston from one end of the cylinder to the other, a throttle valve member in the by-pass, the body being formed with a second by-pass around the throttle valve member, a second throttle valve therein, and 0perable to fully close before the first throttle valve,

an operating member common to both throttle i valves, a control carried by the socket and located to engage the quadriceps extensor tendon of the stump to be motivated by the tensioning and relaxation thereof, the throttle valves being open when said tendon is relaxed, and motion transmitting connections between the control and the operating member for the throttle valves.

9. An artificial leg for above-the-knee amputees including a stump socket, a lower leg including a tibia member hinged by a knee joint tothe socket and carrying a foot, a hydraulic knee lock and brake carried. by the lower leg and including a link which includes a cylinder piv-'- oted to the frame at the foot end thereof and a piston having its rod pivoted to the socket below and eccentric to the hinged axis of the knee joint, a valve body carried by the cylinder and formed with a by-pass around the piston from one end 'of the cylinder to the other, a throttle valve memberm the bypass, the body being formed with a secondby=pass around thef throttle valve her, a second throttle valve therein, and operablethe quadriceps 'extensor tendon of the stumpto be motivated by the tensioningand relaxations thereof, and motiontransmitting connections between the control and the actuator member for the throttle valves.

'10. An artificial legfor above-the knee ain'- putees including a stump socket, a lower leg in;- cluding a frame hinged by a knee joint to the socket and carrying a foot, a hydraulic-knee lock and brake carried by 'the lower leg and including a link which includes a cylinder pivoted 'to the tibia member-at the foot end thereof, and a piston having its rod 'pivote'd 'tothe socket below and eccentric to the hinged axis of the knee joint, a valve body carried by the cylinder and formed with a -by-pass around the piston from one "end of the cylinder to the other, a throttle valve member in the by-pass, the body being formed with a relief valve by 'pa'ss around the throttle valve, a closed relief valve therein arranged to open under abnormal pressure in the cylinder on one side of the piston when the throttlevaive is operated out of fully open position, a control carried by the socket in position to engage the quadriceps extensor tendon and be motivated by the tensioning and relaxation thereof, and motion transmitting connections between the 'co'n-- trol and the throttle valve actuator member.

11. An artificial leg for abovethe-knee aimputees including a stump socket, a lower leg including a frame hinged by a knee joint to the socket and foot pivoted: at the ankle to the tibia member, a knee lock and brake mechanism including a link including upper and lower endwisely relatively movable sections, one pivoted at its upper end to the socket below and eecentrie to the hinge axis of the knee joint, and the other being pivoted at its lower 'end' to the ankle pivot of the foot, a brake "acting on the sections to limit the relative 'endwi'se movement thereof and brake and lock the socket and lower leg from movement about the hinge knee joint, a'n actu= ator member for the brake, a fibula link including two sections and a friction slip joint between them, one section being pivoted at its upper end to the socket eccentric to the hinge axis of the knee joint and the other section at its lower eh?! to the foot in advance 'of the ankle pivot, a control for the brake on the socket and located to be motivated by the action of the quadriceps 'ex'tens'o'r tendon and motioii transmitting connectlon's between the control and the brake aetil 'at'or member.

l2. A'n artificial leg ror-a ove-uwknee ambittees including a stump socket, a lower leg ineluding a frame hinged by a knee joint to the socket and foot pivoted at ankle to the frame, a knee lock and brake mechanism including a link including upper and lower 'e'ridwisely relatively movable sections, the lower section bein pivoted at its lower end to the ankle pivot of the foot and includinga 'oy-linder'foia hydraulicfliii'd, the upper section including a pistonsin the'cylinider and havin its rod pivotedfto the socket-eccentric, to the axis hinge knee -joint, a valve. body having a by-pass from one end of the cylinder to the other around the piston, a throttle valve in the by-pass, a fibula link including two sec tions and a friction slip joint between them, one section being pivoted at its upper end to the socket eccentric to the hinge axis of the knee joint, and the other section being pivoted to the foot in advance of the ankle joint, a control for the brake on the socket in position to be motivated by the action of the quadriceps extension tendon, and motion transmitting connections between the control and the brake actuator members.

13. An artificial leg for above-the-knee amputees including a stump socket, a lower leg including a tibia member hingedby a knee joint to the socket and carrying a foot, a hydraulic knee lock and brake carried by the lower leg and includin a link which includes a cylinder pivoted to the frame at the foot end thereof, and a piston having its rod pivoted to the socket below and eccentric to the hinge axis of the knee joint, a valve body carried by the cylinder and formed with a by-pass around the piston from one end of the cylinder to the other, a throttle valve member in the by-pass, an operating member therefor for closing and opening the same, the cylinder having a spring pressed plunger at its upper portion above the piston, the piston rod extending through the plunger, and a floating followup piston in the lower end of the cylinder, and a control on the socket operated by the quadriceps extensor tendon during the tensioning and relaxation thereof, and motion transmittin connections between the control ad the actuator member for the throttle valve member.

14. An arificial leg for above-the-knee amputees including a stump socket, a lower leg including a tibia member hinged by a knee joint to the socket and carrying a foot, a hydraulic knee lock and brake carried by the lower leg and including a link which includes a cylinder pivoted to the foot end thereof, and a piston having its rod pivoted to the socket below and eccentric to the hinge axis of the knee joint, a valve body carried by the cylinder and formed with a by pass around the piston from one end of the cylinder to the other, a throttle valve member in the by-pass, an operating member therefor for closing and opening the same, an axially movable spring abutment in the upper end of the cylinder and extending axially above the cylinder, a plunger in the upper portion of the cylinder, a spring between the abutment and the plunger, a floating follow-up piston in the lower end of the cylinder, the piston rod having a shoulder located to engage and depress the abutment as the piston approaches the end of the downward movement in the cylinder, the piston rod sliding through the plunger and the abutment, a control on the socket operated by the quadriceps extensor tendon during the tensioning and relaxation thereof, and motion transmitting connections between the control and the actuator member for th throttle valve member.

15. An arificial leg for above-the-knee amputees including a stump socket, a lower leg including a tibia member hinged by a knee joint to the socket and carrying a foot, a hydraulic knee lock and brake including a link which includes a cylinder pivoted to the frame at the foot end thereof, and a piston having its rod pivoted to the socket below and eccentric to the hinge axis of the kne joint, including a valve body carried by the cylinder and formed with a bypass around the piston from one end of the cylinder to the other, a throttle valve member in the by-pass, the body being formed with a relief valve by-pass around the throttle valve,a closed relief valve therein arranged to open under abnormal pressure in the cylinder above the piston when the throttle valve is operated out of fully open position, the cylinder having a spring pressed plunger at its upper portion, the piston rod extending through the plunger, a control carried by the socket in position to engage muscles of the thigh acting during the walking cycle and be motivated by the tensioning and relaxation thereof, and motion transmitting connections between the control and the throttle valve operating member.

JOHN G. CATRANIS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 758,020 Robinson Apr. 19, 1904 1,438,696 Cinquini Dec. 12, 1922 1,998,873 Kingsbury Apr. 23, 1935 2,305,291 Filippi Dec. 15, 1942 FOREIGN PATENTS Number Country Date 132,533 Great Britain Feb. 17, 1921 306,870 Germany July 17, 1918 319,342 Germany Mar. 4, 1920 530,887 France Oct. 12, 1921 

